blowpipe



Oct. 12,1937. H. w. cowlN BLOWPIPE Filed Jan. 10, 1935 INVENTOR H ERBERT W. COWIN I AOE Patented Oct. 12, 1937 STATES ATENT oFFieE Claims. (01. 158-274) This invention relates to blowpipes for use in welding, cutting and similar operations where a heatingflame is to be used either alone or in connection with a gaseous cutting jet. Them- 5 vention has particular application to blowpipes for use in general light duty diversified hand operations.

It is desirable that blowpipes of this character be so constructed that they may conveniently and economicallyperform a varietyof operations. In certain operations," as'in cutting through thick steel or cast iron, a hot preheating flame is desirable and, for best results, combustion of the fuel gas is preferably supported by commercially pure oxygen. In other operations, less intense heat may bemore satisfactory and more economical, as in cutting through comparatively thin steel, in deseaming, and in low velocity rivet cutting; and, for such purposes, atmospheric air may be mixed to advantage with one of the components of the combustible mixture prior to mixing such components together. 7

It, is also desirable that adaptation of the apparatus to the various operations presented should not be dependent on the variable judgments of the several individuals who use the apparatus from time to time,and that the-apparatus be as nearly proof as possible against accidental closing of the air intake under conditions where induction of air into the gaseous heating mixture is desired.

It is an object of the invention, therefore, to.

provide an improvement in blowpipe construction whereby a single blowpipe may be adaptable interchangeably to a variety of operations and which has incorporated therein the desirable features enumerated above.

Other objects and novel features of the invention will be apparent from the following description taken with the accompanying drawing, in

which:

Fig. 1 is a view in elevation of a cutting blowpipe embodying this invention, showing parts in section; r

Fig. 2 is a fragmentary detail view, in plan, showing the relation of the air induction plug to the valve body;

Fig. 3 is a sectional view on line 33 of Fig. 1;

Fig. 4 is a fragmentary sectional view on line 4-4 of Fig. 3 but on an enlarged scale, showing the relation of the air induction plug to the air injector; and V Fig. 5 is a detail sectional view of a plug which may be substituted for the air induction plug 5 shown in Fig. 4.

The blowpipe shown in the drawing comprises a head N having a cutting nozzle N attached thereto, the head being connected with a handle H by a plurality of gas-conducting pipes.

Pipes A and 0 respectively conduct the com- 5 bustible mixture and the cutting gas to the head N and-the nozzle N; and a branch pipe O a cross. passage P, and a return branch pipe 0 together provide a long conduit to conduct the preheating oxygen or combustion-supporting gas 10 to the head N and back to the point where this gas and the fuel gas are mixed. V

The handle H comprises a front block F and a rear or valve block R connected by a tubular casing C; the front and rear blocks or bodies 15 constituting spaced supports for the several pipes just described. Within the rear block R is formed an oxygen inlet passage 0 leading to a chamber Iii from which passages H and I2 branch and: respectively connect with pipes O and 0 see Figs. 1 and 3. Flow of oxygen from chamber l0 into passage H is under control of a valve V operable through a control lever 13, and flow of oxygen from chamber Ii) into passage I2 is under control of a throttle valve [4. 25

Atmospheric air may be mixed with one of the components of the combustible mixture, in the present case with the oxygen, before such airdiluted mixture is admixed with the other component, e. g., a fuel gas such as acetylene. To 30 this end an injector nozzle I5 is secured within a chamber l6 in the block R. and forming a part of passage 0, see Figs. 3 and 4. When the apparatus is in operation, oxygen discharges from the forward end of the nozzle I5 so as todraw in air 35 from the atmosphere through an annular distributing chamber I8 surrounding the forward end of the nozzle. Air is admitted to chamber l8 through a bore l9 formed in a threaded plug 2|] removably secured in an aperture 2| in the wall 40 of chamber l8. The plug 20 has a hexagonal head 22 which is preferably provided with a plurality of radial air inlet passages 23 connecting with bore I9, as clearly shown in Fig. 4.

The plug 20 may be replaced, for certain work, 45 by a solid, imperforate plug 24, see Fig. 5, whereby the chamber I8 is closed to the atmosphere and only commercially pure oxygen from passage I2 is mixed with the fuel gas. At such times nozzle l5 may be removed, if desired, by removing 50 a plug 25'whichcloses the rear end of chamber H5 in which the nozzle I5 is located, and removing the annular retainer 26 threaded into the chamber l6.

After passing through chamber I 8, the oxygenthe nozzle 29 and is connected to a fuel-gas inlet 1 passage 30. See Figs. 1 and 3.

A valve 32 controls the flow of fuel gas through passage 30. Nozzle 29 may be removably held in chamber 28, in a manner similar to nozzle l5,v by a ring screw 33 threaded into the bore of the chamber 3|; and the rear end of this chamber may be closed by a removable plug 34v threaded into the bore. V

It willv be understood that the invention may be embodied. in other types of blowpipes, and that numerous changes may be made in the structural details here illustrated without departing from theprinciples of theinvention.

.Iclaim:

. 1. In a blowpipe, the combination of a body having .a fuel gas passage therethrough; a com.- bustion-supporting gas passage leading to and discharging into the fuel gas passage; an air intake leading tosaid combustion-supporting gas.

passage; and a removable-plug inlsaid' air intake having an axial passageand a plurality of passages disposed radially of said axial passage forming communication between the latter and the; atmosphere. 7 V

= 2. In a blowpipe, the combination of a fuel gas conduit; an injector nozzle in said conduit; a combustion supporting gas conduit communicating with the fuel gas conduit through said nozzle; a second injector nozzle located in the combustion-supporting gas conduit; and a plug in the wall of the last-named conduit and having a passage therethrough forming communication between the atmosphere and saidlast-named conduit.

3a In a blowpipe, the combination of a body havinga'fuelgas conduit therethrough; an injector nozzle in said passage; a combustion-supporting gas conduit communicating with the fuel gas passage through said nozzle; a second injector nozzle located in the combustion-supporting gas conduit; and a plug in the wall of the lastnamed conduit having an axial passage terminating adjacent the discharge end of said second injector nozzle, said plug having radial passages communicating with said axial passage and with the atmosphere.

l. In a blowpipe, the combination of a body having two chambers, a fuel gas inlet, and an oxygen inlet; a removable injector nozzle in one of said chambers and. communicating with said 7 oxygen inlet; a perforate plug removably secured to said body and having the passage thereof opening into said chamber containing said nozzle, to admit air to be mixed with oxygen passing through said nozzle; and means, including an injector device in the other of said chambers, for drawing fuel gas through said fuel gas inlet into said other chamberand for delivering the. oxygen-air mixture to. be mixed with such inducted fuel gas.

.5 In a blowpipe, the combination of a head; a; nozzle carried; by said head for delivering a combustible gas mixture; a body having separate inlets for oxygen and afuel gas; an injector in said: body. communicating with said nozzle; a handle between said head and said body; a conduit having two portions, the first portion extending from the oxygen. inlet through said handle to said head, the second portion extendingfrom said head through said handle back to said bodyand communicating with said injector, and the head ends of said conduit portions communicating with one another; a passage in said body. between the fuel gas inlet and said injector; means whereby air may be admitted to the first. portion of said conduit, said means comprising a perforate plug: removably secured to said body; and an injector insaid body in said first conduit portion adjacent said plug to draw inair from the atmosphere and mix such incoming air with oxygen admitted through said oxygen inlet.

HERBERT W. COWIN. 

